Characterization of the feeding behavior of the Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae) on finger limes and finger lime hybrids using electropenetrography (EPG)

Candidatus Liberibacter asiaticus (CLas) is a phloem-limited bacterium transmitted by the Asian Citrus psyllid, Diaphorina citri, and associated with the most destructive citrus disease, Huanglongbing (HLB) or citrus greening. Disease management mainly relies on chemical control. The production of tolerant and/or resistant host plants through breeding can provide a sustainable and effective method for long-term management. Recently, finger limes and their hybrids have displayed tolerance to HLB suggesting that acquisition and inoculation of CLas by D. citri may be different than for susceptible host plants. Therefore, the objective of our study is to compare the probing behavior of D. citri adults and CLas transmission on finger limes (Citrus australasica F. Muell) and three hybrids (PFL1-11; PFL1-3; PRL1-55) with susceptible Valencia sweet orange (Citrus × sinensis (L.) Osbeck) using Electropenetrography (EPG). 24-h EPG recordings were done with AC-DC monitors at 10⁹ Ω input resistance (Ri) and 150mV substrate voltage. Host plants and psyllids used during EPG were tested by quantitative PCR to correlate their feeding behavior with CLas acquisition and transmission. Quantitative variables such as time to the first phloem contact, number, and duration of phloem salivation (E1) and phloem ingestion (E2) will be calculated.